Multiple stitch pattern producing mechanism



United States Patent Primary ExaminerRichard J. Scanlan, Jr.

[72] lnventor William Alexander Watson Duntocher, Scotland, UnitedKingdom Attorneys- Marshall 1. Breen, Chester A. Williams, Jr. and F.[21] App1.No. 744,493 Donald an [22] Filed July 12,1968 [45] PatentedNov. 24, 1970 [73] Asslgnee The singer (:ompany ABSTRACT: A mechanismfor a sewing machine comprising New York, New York a conventional zigzagcam having superimposed upon it 111 a corporation of New Jersey spacedrelation a substantially similar upper zigzag cam modified so that apredetermined number of spaced cam lobes [54] MULTiPLE STITCH PATTERNPRODUCING are removed from thelatter cam. Superimposed upon the con-MECHANISM I ventional zigzag cam in face-to-face relation 18 a second orm- C im 9 Drawing Figs termediate zigzag cam which is similar in designto the aforementioned modified zigzag cam and is operatively associated[52] U.S .Cl. 112/158, with h fi or upper difi d cam and theconventional 74/568 cam, so that indexing of the upper modified cam willeffect Int-Cl Dosh 3/02 movement of the second modified cam through aredeter- P [50] Field of Search 1 12/158, i d b r of degrees, wherebythe void between the cam 73, 11 1; 74/568 lobes on the conventionalzigzag cam will be more fully filled 56 R f d when the cams are soindexed to preferably, a blindstitch posi- 1 e erences I e tion.Adjustment of the cams relative to each other is effected UNITED STATESPATENTS by having a portion of the periphery of a disk to which the1,524,461 1/1925 Speer 74/568 upper modified cam is attached projectthrough an opening in 2,594,911 4/1952 Goff 74/568 the bracket arm coverarranged to be shifted by the finger of 2,800,808 7/1957 Cappelle et a1.74/568X the operator. Detent means operatively associated with the2,999,471 9/1961 Bennink et al 112/158 disk is provided for locking thesuperimposed cams in their 3,039,323 6/1962 Mori 74/568 selectedrelative position.

a V l I I I 26' -4 80 iew-= lu n 5 M 1 42 1 B g 31 a... 23 2| PatentedNov. 24, 1970 3,541,981

JNVENTOR. 2 William A. Watson I ATTORNEY Patented Nov. 24, 19703,541,981

STITCH WIDTH NEEDLE POSITION INVENTOR.

William A.Wafson MULTIPLE STITCH PATTERN'PRODUCING MECHANISM BACKGROUNDOF THE INVENTION 1. Field of the Invention This invention pertains to amechanism for manually changing the relative phase relationship of thecams in a sewing machine of the zigzag type in order to producedifferent selected stitch patterns of high quality and for accomplishingthe same in a relatively simple and quiet manner.

2. Description of the Prior Art It is generally known in the art toprovide in a sewing machine means for changing the stitch pattern. Anunsatisfactory arrangement which heretofore has been used to achievethis end comprises a removable cam designed so that it can be mounted ona driven camshaft in one of two positions which are substantially 180apart. In order to produce a stitch pattern different from the onepreviously formed the operator of the machine is required to remove thereplaceable cam, turn it through 180 and replace the cam in its latterturned position on the camshaft. This type of arrangement requires asubstantial amount of effort on the part of the operator and alsorequires a rather complicated mechanism compared to that required in theuse of the present improvement. Other arrangements for altering thestitch pattern are relatively inconvenient to operate and are not asreadily accessible to the operator of the sewing machine as is thepresent invention. In addition, certain of the previously developedmechanisms are notorious for having a relatively noisy mode ofoperation, which is undesirable to the operator of the machine and thosenearby.

SUMMARY This invention relates to the art of sewing machines preferablyof the zigzag type, and more particularly to a novel and improved cammechanism comprising a plurality of relatively phase shiftable camswhereby one of a plurality of predetermined stitch patterns may beselected manually by modifying the angular relationship of the cams in asimple and efficient manner to transmit to the needle carrying needlebar by way of a cam follower and transmission means, a needlejoggingmotion in conformance with the selected pattern sensed by the camfollower. Further, the cams are so arranged relatively to each otherthat the cam follower will sense the stitch pattern therefrom with aminimum amount of noise.

The present invention overcomes the above discussed prior artdeficiencies and more, by providing a mechanism for selecting apredetermined stitch pattern comprising three coaxially mounted camsadapted to be attached on a rotatable shaft journaled in the frame ofthe sewing machine wherein one cam is by way of illustration of theconventional zigzag variety and has superimposed upon it in spacedrelation, for example, a first or upper similar zigzag cam modified sothat every third cam lobe is removed. Superimposed upon the regularzigzag cam in contiguous or face-to-face relation therewith a second orintermediate cam, illustrated as being of the zigzag variety, which issimilar in design to the upper modified zigzag cam and slidably carrieson its upper surface adjacent the upper modified cam, an actuating platehaving a downwardly extending pin registering with a camming slotprovided in the intermediate cam. A downward projecting stud carried bythe upper modified cam registers with an open ended aperture formed inthe actuating plate so that indexing of the cam will effect movement ofthe plate, which, in turn causes a corresponding movement of theintermediate modified cam through a predetermined number of degrees.Manual adjustment of one cam relative to the other is effected by havinga portion of the periphery of the disk to which the upper modified camis attached preferably projecting through an opening in the bracket armcover in position to be shifted by the finger of the operator foraltering the combined stitch pattern response of the cams to produce oneof two or more stitch patterns. It is to be understood that theforegoing cams are not limited to the zigzag variety and do notnecessarily have to produce a zigzag stitch pattern in any one of theirselected relative positions. It is intended to be-within the scope ofthe present invention to provide a plurality of cams of differentstitch-pattern response-producing surfaces which when indexed produce apredetermined integrated response the pattern of which is determined bythe relative orientation of the stitch-pattern response-producing camsurfaces. In the preferred embodiment this end is accomplished by virtueof the cam design and their shiftable mounting arrangementso that in oneposition the cam lobes of the plurality of cams are in substantialvertical register and a regular zigzag seam is produced, and when theupper modified cam is indexed by means of the finger actuatable disk thelobes on it move through a predetermined number of degrees relative totheir previous zigzag position and the intermediate cam is moved bymeans of the pin in the actuating plate so that its lobes are moved apredetermined fraction of said number of degrees relative to theirprevious position. Thus, the cam follower is allowed to drop to the lowpoint on the lowermost zigzag cam only once every six needlepenetrations, thereby resulting in the production of a blindstitch seam.These seams are merely illustrative of the stitch patterns which may beproduced by such a cam mechanism. When intelligence is added to thelower standard zigzag cam as discussed above, the portion of thestitching cycle during which the follower senses the high point of thecombined cam response functions in an extremely quiet mode of operationsince the orientation of the cam lobes of the modified cams relative tothose of the zigzag cam provide a substantially continuous responsesurface. Thus, there is provided by the present invention a novel andimproved construction for a cam indexing mechanism which avoids deficiencies of the previously designed devices.

Accordingly, it is a primary object of the present invention to providefor use in a sewing machine of the ornamental stitch variety, a noveland improved cam mechanism which is easily adjusted and is readilyaccessible to the operator of the machine, and which when adjusted willpermit the operator to select one or more different stitch patterns.

Another object of the present invention is to provide in a zigzag sewingmachine, a manually-actuatable relatively noiseless mechanism foraltering the angular relation of the cams to produce a desiredpredetermined stitch pattern.

It is a further object of this invention to provide for use in a sewingmachine of the ornamental stitch variety, a relatively quiet operatingmechanism for changing the stitch pattern normally produced by arrangingthe mechanism so that it is readily accessible to the finger of theoperator and need not be completely removed to alter the stitch pattern.

A further object of the present invention is to provide for use in asewing machine of the ornamental stitch variety, a plurality of cams ofdifferent stitch-pattern response-producing shape adapted for relativeangular movement and for being locked in a selected relative position.

Having in mind the above and other objects that will be evident from anunderstanding of this disclosure, the invention comprises the devices,combinations and arrangements of parts as illustrated in the presentlypreferred embodiment of the invention which is hereinafter set forth insuch detail as to enable those skilled in the art readily to understandthe functions, operation, construction and advantages of it when read inconjunction with the accompanying drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of thecam indexing mechanism and its related components constructed inaccordance with the present invention oriented to produce a first stitchpattern;

FIGS. 2 (a); (b), and (c) comprise a step-by-step assembly showing therelative position of the parts comprising the cam mechanism of thepresent invention for ultimately producing a first stitch pattern;

machine bracket arm and cover constructed in accordance with the presentinvention;

FIG. 5 is a vertical sectional view taken substantially on the line 5-5of FIG. 4;

FIG. 6 is a vertical sectional view taken substantially on the line 66of FIG. 5;

FIG. 7 is an exploded perspective view of the cam indexing mechanismembodying the present invention.

FIG. 8 illustrates a zigzag stitch pattern produced by the needle withthe cams oriented as shown in FIG. 2;

FIG. 9 illustrates a blindstitch pattern produced by the needle with thecams oriented as shown in FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS- Referring now to theaccompanying drawings wherein like reference numerals designate similarparts throughout the various views, the preferred embodiment of thepresent invention is herein disclosed as embodied in a sewing machinesubstantially similar to that forming the subject matter of U.S. Pat.NO. 3,051,107, granted Aug. 28, 1962 to Ralph B. Johnson and assigned tothe assignee of the present application, to which reference may be hadfor a more complete understanding of the machine. The presentapplication describes the parts of the sewing machine only to the extentnecessary for a complete and thorough understanding of the presentinvention.

The sewing machine includes the usual bed (not shown), a standard 10risingfrom one end of the bed and carrying a bracket arm 11 thatterminates in a head (not shown) overhanging the bed. The top of thebracket arm 11 is open and normally is closed by a top cover plate 12.Rotatably journaled in suitable bearings provided in the bracket arm 11is a horizontally disposedmain shaft 13 extending length wise of thebracket arm and carrying at one end a suitable drive mechanism (notshown). At its opposite end, the main shaft 13 carries a counterbalancedcrank 14 connected in the usual manner to a vertically disposed needlebar 15.

In the head of the machine there is mounted for endwise reciprocationand sidewise movement the needle bar 15 having a needle 16 secured toits lower end by a standard needle clamp 17. Upon actuation of theneedle bar 15 the needle penetrates the work W (see FIGS. 8 and 9)disposed below it on the work surface of the sewing machine andcooperates in the usual manner with asuitable. stitch forming mechanism(not shown) located below the head in the bed of the machine to form anornamental stitch pattern, preferably a zigzag stitch (FIG. 8) or ablindstitch pattern (FIG. 9). As readily can be seen from theblindstitch pattern of FIG. 9 the needle 16 is maintained laterallyfixed by a needle jogging mechanism including the needle bar 15 at theline of feed of the work W for a predetermined number, preferably four,of straight stitches (5,. S S S and then is moved laterally of the lineof feed to produce a predetermined number, preferably two, of zigzagstitches -.Z,, A In the preferred embodiment, as shown in FIG. 9 twozigzag stitches are formed after every four straight stitches. Uponselection of the zigzag stitch pattern shown in FIG. 8, the needle for15 is vibrated laterally for a predetermined stitching cycle therebycausing-the needle 16 to move laterally of the line of feed of the workW so that upon alternate stitches it will penetrate the work atlaterally spaced points to define an ornamental stitch pattern, such asthe zigzag seam shown in FIG. 8..

To accomplish the above described stitch patterns the needle bar 15 ismounted for endwise reciprocation in a pair of vertically spaced bearinglugs 18 and 19 of a swinging needle bar gate 20. To provide for lateralvibration of the needle bar 15, the gate 20 also includes a pair ofvertically spaced upper and lower bearing lugs 21 and 22, respectively.formed with bores (not-shown) for receiving a central portion of a pivotrod 23 which mounts the gate 20 for pivotal movement about the axis ofthe central portion of the rod 23. For purposes of the present inventionit is sufficient to say that the head of the sewing machine mounts thepivot rod 23 in a pair of vertically spaced bosses, referencebeing hadto the above identified patent for a more complete description.-

Pivotal movement of the needle bar gate 20 about the axis of the centralportion of the rod 23 is imparted there to by means of a pitman 24adjustably connected at its needle bar end to an L-shaped bracket 25 bymeans of a hexagonal type screw 26 extending through the bracket andthreaded into the pitman. The bracket 25 is pivotally connected to theneedle bar gate 20 by a pin 27 secured to the gate by a setscrew (notshown) or other suitable means. The other end of the pitman 24 extendsthrough a horizontally orientated open ended slot 28 formed in a plate29 that is pivotally mounted on a stud pin 30. The pin 30 is carried ina substantially U-shaped bracket 31 pivotally supported on a stud 32secured in the frame ofthe bracket arm of the sewing machine. As bestshown in FIG. 1, on the side of the plate 29 furthest from the needlebar 15, there is mounted on the end of the pitman 24 an upstandingcircular shaped portion 33 disposed in abutting relation to theadjoining surface of the plate 29. The end of the pitman 24 adjacent theplate 29 is adapted to be slidably shifted along the horizontal slot 28to vary the zigzag amplitude or stitch width at the needle by means of amanually shiftable lever having at one end thereof an upstanding pin 35secured to a spring member 34 maintained in slidable register with anopen ended U-shaped slot 36 provided in an offset shelf member 37secured to the pitman 24 in a suitable manner, and at its other end'ahandle 38, also carried by the member 34, which is readily accessible tothe operator of the machine. To vary the field or centerline of thezigzag pattern there is provided a handle 39 carried by a plate 40 whichis secured to the bracket 31, whereby the bracket pivotally may beshifted about the stud 32.

Theplate 29 is oscillated by a rotary pattern cam arrangement comprisinga plurality ofcam disks 41,42 and 43 having corresponding peripheralpattern surfaces 44, 45 and 46. The cams 41, 42 and 43 operably coactwith other related parts, to be described in detail hereinafter, to forma cam indexing mechanism generally designated 47 for oscillating theplate 29 in a predetermined selected manner, which, in turn, operablycauses the needle 16 to produce preferably either a zigzag stitch or ablindstitch pattern. The cams 41, 42 and 43 releasably are secured by ashouldered thumb screw 48 threaded in a bore 49 formed in a disk adapter50, which is journaled on a cam shaft 51 supported by the member 34. Thedisk adapter has integrally formed therewith a gear wheel 52 whichmeshes with a worm gear 53 disposed on the main shaft 13. A single camfollower generally designated 54 a laterally extended shelf portion 55formed with the plate 29 and has a cam follower element 56 for trackingthe peripheral surfaces 44, 45 and 46 of the cam disks 41,42 and 43.Thus, as the cam follower element 56 senses the combined stitch-patternresponse of the cam surfaces 44, 45 and 46 it conveys the trackedpattern to the plate 29, thus causing it to move in conformancetherewith and resulting in a corresponding movement ofthe pitman 24,which vibrates the needle 16 carried by the needle bar 15 to produce theselected stitch pattern.

A torsion spring 57 coiled about the intermediate portion of the pivotrod 23 between the bearing lugs 21 and 22 is constructed and arranged tobias the needle bar gate 20 in a co unterclockwise direction therebytending to pull the pitman 24 to the left which urges the peripheryofthe upstanding portion 33 against the adjacent surface of the plate 29causing the plate to pivot about the pin 30 in a clockwise direction.Thus, since the cam follower element 56 is mounted on the plate 29 byway of the shelf 55 it also will tend to move clockwise and will beresiliently maintained in tracking engagement with the cam surfaces 44,45 and 46. As the cam surfaces present a high point to the cam followerelement 56, it will tend to move in a'counterclockwise directionimparting a corresponding clockwise motion to the needle bar gate 20against the action of the normal bias of the spring 57. When thefollower element 56 contacts a low point on the cam surfaces the needlebar gate is pivoted in a counterclockwise direction by the spring 57.

To provide the operator with a but, as of stitch patterns the cams aredesigned so that in one position a blindstitch will result, while inanotherselectedposition a conventional zigzag stitch pattern will beproduced. As best shown in FIG. 7, the cam 41 is of a conventionalzigzag design with equally spaced cam lobes 58 forming the high pointsand the low pointsv defined by the surfaces 59 therebetween. The cam 41may be of any desired design, but as shown in the drawing, is preferablyof the eighteen stitch variety. The zigzag cam 41 is formed with akeyhole shaped aperture generally designated 60 comprising an enlargedcircular portion 61 for mounting the cam on the adapter 50 and arelatively narrow elongated opening or slot 62 depending therefrom. Theadjacent or intermediate cam 42 is illustrated as having six cam lobes63 and is similar to the zigzag cam 41 except that it is modified sothat every third cam lobe is removed. The modified cam 42 is mounted incontiguous relation with the zigzag cam on the cam shaft 51 so that itcan be manually shifted angularly about the axis of the cam shaft tochange its phase relation with respect to the standard zigzag cam 41.The intermediate cam 42 slidably carries on its upper surface adjacentthe upper cam 43, an actuating plate-64 having a downwardly extendingpin 65 registering with a camming slot 66 formed in the intermediate cam42. The intermediate cam 42 coaxially mounts with the cam 41 by means ofan opening 67 comprising a cenoverlapping circular portions 71 and 72for slidably mounting the plate 64 on the adapter 50 with the pin 65 inregister with the slot 66 of the cam 42, as best shown in FIG. 6. Theupper cam 43 is of a design similar to that of the intermediate cam 42including six cam lobes or high points denoted by the reference numeral73 with low'points comprising the surfaces 74 disposed between the camlobes. The cam 43 also is provided with an opening 75 for coaxiallymounting the cam 43 on the adapter 50 with the cams 41 and 42 and theactuating plate 64. This latter opening is similar in shape to theopening 67 formed in the intermediate cam 42. There is provided stud 76depending downward from the cam disk 43 for register with an open endedaperture 77 formed on the periphery of the actuating plate 64. The stud76 is arranged relative to the earns 42 and 43 so that'indexing of thecam 43 through a certain number of degrees will effect sliding movementof the actuating plate 64 from portion 71 to 72 or vice versa, which inturn causes a corresponding movement of the intermediate cam 42 througha predetermined fraction of the degrees through which the cam 43 hasmoved.

As shown in FIG. 2, in one position the cam lobes 63 and 73 of themodified cam 42 and 43, respectively, are alined in vertical registerwith the lobes 58 of the regular zigzag cam 41 and a regular zigzag seamsuch as the one shown in FIG. 8 is produced. The illustrations a, b andc of FIG. 2 show the phase previous zigzag position shown in FIG. 2a, orin other words the cam lobes of the cam 42 only move throughsubstantially one-half of the angular distance moved by the cam lobes 73of the upper cam 43. This movement is determined by designing theactuating plate 64 so that it shifts a limited amount only that issufficient to locate the cam lobes of the cams in the positionillustrated in FIG. 3c Thus, by virtue of the above arrangement the camfollower element 56 is allowed to contact the low points or surfaces 59on the zigzag cam 41 only once every six needle penetrations, therebyresulting in the production ofa blindstitch pattern such as illustratedin FIG. 9.

With the cam lobes disposed as shown in FIG. 3, that is, for blindstitchoperation, the outer surfaces of the adjacent lobes 58, 63 and 73provide a substantially continuous peripheral surface-denoted by thereference numeral 78 for the cam follower element 56 to track duringformation of the straight stitches comprising the blindstitch pattern. Aconstant problem which accomplishes the foregoing mechanism is that anyspacing or voids that normally may exist between the adjacent cam lobescomprising the straight stitch portion of the stitching cycle will causea substantial amount of undesirable noise and also, naturally willaffect the quality of the resulting blindstitch pattern. In thepreferred embodiment of the present invention any spacing thatheretofore has existed between adjacent cam lobes is minimized so thatas the follower leaves the peripheral surface of, for example, a lobe58, it immediately contacts the peripheral surface of the next lobe 63and that of the lobe 73 in seriatim and so on. This results in arelatively quiet mode of operation and a blindstitch pattern of thedesired quality. It readily can be seen from FIG. 3a and 30 that by theabove described operation the cam lobes 63 and 73 of the modified cams42 and 43, respectively, are indexed to a position between the lobes 58of the zigzag cam 41 to fill any void therebetween.

The modified cam 43 preferably is integrally formed with a manuallyoperable actuating dial or disk 79 having a knurled peripheral surface80. A portion of the periphery 80 ofthe dial 79 is adapted to projectthrough a slot 81 provided in the cover plate 12 for the bracket armHand is positioned, as best shown in FIG. 4, to be readily. accessibleto the finger of the operator. The dial 79 mounts on the disk adapter inrotary fashion so that the modifiedcam 43 is superimposed upon theregular zigzag cam 41 in spaced relation and the intermediate cam 42 issuperimposed upon the cam 41 in face-to-face relation as shown in FIGS.land 5. The opening 75 comprising a circular portion and a fan-tailportion depending therefrom formed in the integrally formed dial 79 andcam 43 allows the cam to be mounted coaxially with the zigzag cam 41 andthe cam 42, and to be shifted relative thereto as described above.

In order to lock the three superimposed cams and the plate 64 in aselected relative position there is provided an apertured detent springgenerally designated 82 including a slightly relation between each ofthe elements comprising the mechanism.

When the upper modified cam 43 is indexed in amanner to be describedbelow, the lobes 73 on the cam are moved through an angular distance ofsubstantially 26 (see FIG. 30 relative to their previous zigzag positionof vertical alinement (see FIG. 20). Movement of the cam 43 causes thestud 76 depending therefrom to slidably shift the actuating plate 64from its zigzag position shown in FIG. 2b to its blindstitch positionshown in FIG. 3b Thus, by means of the actuating plate pin operativelycoacting with the slot 66 formed in the modified cam 42, the latter camis shifted so that its lobes 63 are moved approximately 13 16 (see FIG.3a) relative to their downward biased integral finger 83 extendingradially thereof and having a detent 84 formed on the lower surfacethereof at its free extremity. The aperture in the spring 82 is similarto that formed in the zigzag cam 41 and comprises a circular portion 85and an elongated opening 86 formed in the finger 83. The spring 82 ismounted adjacent the upper surface of the dial 79 in coaxial relationwith the cam disks 41, 42 and 43, and the actuating plate 64. Theseelements together with the spring 82 are vertically alined in theirproper relative position I by means of a pin 87 depending upward from acurved member 88, which is held in place in a cutout portion (not shown)provided at the top of the gear wheel 52. The member 88 is mounted withthe cam shaft 51 by means of a screw 89 (see FIG. 5) and is designed sothat it is substantially complementary to the portion removed from thetop surface of the wheel 52. The alining pin 87 extends sequentiallyupward through a bore 90 formed in the disk adapter 50. the slot 62 ofthe cam 41, the fantail shaped opening 69 of the cam 42, a radiallylocated hole 91 formed in the actuating plate 64, the fantail shapedportion of the opening 75 of the cam 43, and finally through the slottedportion 86 of the spring finger 83.

A pair of circumferentially spaced depressions 92 and 93 are formed onthe upper surface of the dial 79 for receiving the detent 84 of thespring finger 83 and releasably holding the cams and the plate in theirselected relative position. The depressions are spaced inward from theperiphery of the disk 79 so that their radial location is substantiallyequal to the radial disposition of the detent 84 relative to the axis ofthe cam shaft 51. Each of the depressions is substantially radiallyalined with a side wall 94 and 95 defining the fantail shaped portion ofthe opening 75 in the cam disk 43, so that as the disk 43 is shiftedangularly relative to the pin between the side walls 94 and 95, thedetent 84 will register with one of the depressions 92 and 93.

The operator manually may select either a blindstitch or a zigzag stitchpattern by shifting the projecting peripheral portion of the dial 79either to the right or to the left as shown by the indicia on thebracket arm cover plate 12 in FIG. 4. Thus, when the dial 79 is shiftedto the right for a blindstitch pattern.

' the modified cam 43 secured to the dial 79 is indexed so that thephase relation illustrated in FlG. 3 results with the detent 84 inregister with the depression 93. The detent carrying finger 83 of thespring 82 is biased downwardly to maintain the detent 84 in contact withthe adjacent surface of the dial 79, but is sufficiently resilient toallow the detent to be shifted from one depression to the other. If azigzag stitch pattern is desired the operator merely shifts the dial tothe left as indicated in FIG. 4 whereupon the earns 41, 42 and 43 willbe alined as shown in FIG. 2 with the detent 84 in register with thedepression 92. This latter arrangement is shown in FIG. 1. Thus, it isseen that the radial walls 94 and 95 of the fantail shaped opening inthe dial 79 form stop abutments for the pin 87 thereby defining thelimits of angular shift of the upper cam 43.

The foregoing describes a preferred embodiment of the present invention.However, an alternative for the means by which the earns 42 and 43 areoperatively associated for relative angular movement, compriseseliminating the actuating plate 64 and in its place providing a radialslot in the intermediate cam 42 for receiving the pin 76 depending fromthe upper cam 43, so that the pin then will move the intermediate camsubstantially one half the angular distance through which the upper cammoves when it is indexed. This arrangement also would eliminate the needfor the camming slot 66 in the cam 42.

Numerous other alterations of the structure herein disclosed willsuggest themselves to those skilled in the art. However, it is to beunderstood that the present disclosure relates to a preferred embodimentof my invention which is for purposes of illustration only and not to beconstrued as a limitation of the invention. All such modifications whichdo not depart from the spirit of the invention are intended to beincluded within the scope ofthe appended claims.

lclaim:

1. In a sewing machine having a frame including a bracket arm, a needlecarrying needle bar mounted in said frame for endwise reciprocation andsidewise' movement, a cam stack comprising a first, asecond and a thirdstitch-pattern cam, at least two of said cams having a differentresponse producing shape, a shaft journaled in said frame for rotationabout a single axis, means for mounting each of said cam in superposedrelationship on said shaft for rotation therewith, means for rotatingsaid shaft in synchronism with said needle reciprocating movements, asingle cam-tracking means carried by said frame for tracking andresponding to said cams during a predetermined stitching cycle, meansoperatively connecting said cam-tracking means to said needle bar forjogging said needle sidewise in conformance with the combined responseofsaid cams sensed by said cam-tracking means, said first and secondcams each having an indexing axis about which said first and second camsmay be indexed angularly relative to said shaft, said indexing axesbeing substantially coincident with said single axis, shift means forchanging the relative phase relation of said cams, said shift meansincluding means for indexing said first cam from a first positionthrough a first angle about said indexing axes to a second position andconcurrently indexing said second cam from a first position through asecond angle different from said first angle about said axes to a secondposition, whereby in said first position of each of said first andsecond cams the cam stack is so arranged as to produce a seam of onepredetermined stitch pattern and when in said second position of each ofsaid first and second cams said cam stack is arranged to produce a seamof a dif ferent predetermined stitch pattern.

2. A sewing machine in accordance with claim 1 wherein said shift meansfurther includes a manually engageable member operatively associatedwith one of said cams, and being constructed and arranged so that anoperator ofthe sew ing machine'will have direct access thereto forshifting said cams to produce the desired stitch pattern.

3. A sewing machine in accordance with claim 2 including a cover forsaid bracket arm. said cover having at least one aperture formed thereinfor receiving at least a portion of said manually operative member tofacilitate access thereto by the operator ofsaid sewing machine.

- 4. in a sewing machine in accordance with claim I wherein I theresponse producing surface of said third cam comprises a first number oflobes ofprescribed configuration, the response producing surface of eachof said first and second cams comprises a second number of lobes ofsubstantially the same configuration as the lobes of said third cam,said second number of lobes being less than said first number of lobes,each said first position of said first and second cam being such thatthe lobes of said first cam substantially are alined with the lobes ofsaid second cam and further are alined substantially with certain ofsaid lobes ofsaid third cam for producing a first stitch pattern, andeach said second position of said first and second cam being such thatthe lobes of said cams are offset from each other about the periphery ofsaid third cam for producing a second stitch pattern.

5. A sewing machine in accordance with claim 4 wherein said first cam issuperimposed upon said third cam in spaced relation and said second camis disposed intermediate said first and third cams.

6. A sewing machine in accordance with claim 2 wherein said manuallyengageably member comprises a disk attached to one of said cams, andbeing arranged so that a portion of the periphery of said disk projectsthrough said frame and is adapted to be shifted by the finger of theoperator.

7. A sewing machine in accordance with claim 2 wherein said cams andsaid manually engageable member commonly are mounted on said shaft, andincluding means for locking said cams in a selected relative positioncomprising a detent for releasably engaging one of a plurality ofdepressions formed on said manually engageable member.

8. A sewing machine in accordance with claim 7 wherein each of said camsis provided with an aperture predetermined size and shape, said manuallyengageable member being operably associated with said first cam andbeing provided with an aperture similar to that provided in said firstcam, said locking means comprising a ring member having an integralportion extending therefrom and having a detent formed at its freeextremity, said integral portion being provided with an aperture similarto that provided on said third cam, said cam mounting shaft having a pindepending therefrom for register with all of said apertures, saidaperture ofsaid third cam being so constructed as to preventcircumferential movement of said third cam relative to said pin, saidaperture of said manually engageable member and ofsaid first cam beingso constructed as to allow for circumferential movement thereof relativeto said pin, such that said first cam may be indexed through said firstangle relative to said third cam by indexing of said manually engageablemember by said operator.

9. A sewing machine in accordance with claim 8 wherein said indexingmeans includes an actuating plate disposed between said first and saidsecond cam for transferring a predetermined fraction of the movement ofsaid first cam to said second cam when said first cam is indexed.

10. In a sewing machine having a frame including a bracket arm, a needlecarrying needle bar mounted in said frame for endwise reciprocation andsidewise movement relative to the direction of reciprocation, a mainshaft journaled in said frame, a first, a second and a thirdstitch-pattern cam, said first and second cams each having a firstnumber of substantially similar response-producing cam lobes similarlydisposed about the surface thereof, said third cam having a secondnumber of response-producing cam lobes disposed about the surfacethereof, the lobes ofthe third cam being substantially the sameconfiguration as the lobes of said first and second cams, a shaftrotatably driven from said main shaft about a single axis, said camsbeing mounted in superposed relationship on said driven shaft forrotation therewith, a cam tracking element carried by said frame fortracking the combined stitch-pattern response of said first, second andthird cams sensed by said element, said first and second cams eachhaving an indexing axis about which said first and second cams may beindexed angularly relative to said shaft, said indexing axes beingsubstantially coincident with said single axis, means operablyassociated with said cams being so constructed and arranged for indexingat least said first and second cams angularly relative to each other andrelative to the third cam to alter the combined stitch-pattern responseof said cam surfaces, said indexing means including actuating meansoperably disposed between said first and second cams, said actuatingmeans being constructed and arranged to be shifted into one of twopositions whereupon in one position the cam lobes of said first andsecond cams are arranged to form a plurality of spaced continuoussurfaces with selected cam lobes of said third cam for producing astitch pattern, and in said second position said cam lobes of said firstand second cams substantially are alined with certain of said third camlobes for producing a second stitch pattern.

11. A sewing machine in accordance with claim 10 wherein said actuatingmeans comprises a plate slidably mounted between said first and secondcams for being shifted to either one of said two positions, said platebeing provided with an aperture and a depending pin, a stud carried byone of said first and second cams. said aperture being in register withsaid stud, the other of said first and second cams includinga cammingslot formed therein, said depending pin being in register with said slotand coacting with the walls thereof, so that when said one cam isindexed through a first prescribed angle said plate is slidably shiftedfrom one of said two positions to the other of said positions therebycausing said pin to move said other cam about said shaft, said slotbeing disposed in said other of said cams fo'r indexing said other camthrough a second prescribed angle when said one cam is indexed throughsaid first prescribed angle such that any voids that may exist betweenthe cam lobes forming the continuous surface will be substantiallyfilled by the cam lobes of said first and second cams.

227g? UNITED S TAT ES PATENT OFFICE CERTIFICATE OF CORRECTION PatentNo.3,54l, 981 Dated November 24, 19 0 Inventor(s) illiam AL Watson It iscertified that error appears in the above-identified patent and thatsaid Letters Patent; are hereby corrected as shown below:

" Column 3, line 63 "A should read Z Column 4, line 56 after "54" insertis carried on Column 5, line 9 "but, as" should read choice Column 8,line 42 "engageably" should read engageable Column 10, line 4 after "a"insert first Signed and sealed this 2L .th day of August 1971.

(SEAL) Attest:

EDWARD M.FLETCEER,JR. I WILLIAM E. SCHUYIER, JR. Attesting OfficerCommissioner of Patents

